Colorado and Washington are the two states in the U.S. that have legalized recreational pot use by adults. / AFP/Getty Images

by John S. Adams, USA TODAY

by John S. Adams, USA TODAY

HELENA, Mont. -- A Montana senator on Wednesday introduced an amendment to a House appropriations bill that would bar federal prosecution of medicinal marijuana patients who own or possess firearms.

The amendment to the Commerce, Justice and Science appropriations bill seeks to overturn a 2011 directive from the Bureau of Alcohol, Tobacco, Firearms and Explosives that stated "any person who uses or is addicted to marijuana, regardless of whether his or her state has passed legislation authorizing marijuana use for medicinal purposes, is an unlawful user of or addicted to a controlled substance, and is prohibited by federal law from possessing firearms or ammunition."

"This measure will ensure that patients can hunt, purchase ammunition and protect their homes without fear of prosecution," Walsh said in a statement.

Medical marijuana policy advocates hailed the proposed amendment.

"Montanans take their Second Amendment rights very seriously and hunting is an important part of our heritage and culture," said Chris Lindsey, a legislative analyst for the Marijuana Policy Project.

A second bipartisan amendment introduced Wednesday by Sens. Rand Paul, R-Ky., and Cory Booker D-N.J., would prevent the federal Drug Enforcement Agency from using federal funds to go after medical marijuana operations in states where such operations are legal under state law. The House in May passed a similar measure on a bipartisan 219-189 vote.